DESCRIPTION (Verbatim from the Applicant's Abstract): The hypothesis of this pathologic tissue. The principal investigator has developed from previous NIH funding (R29HL45045) a video camera system based on scattered polarized light which has been shown in pilot clinical trials to improve the doctor's visualization of the epidermis and papillary dermis of the skin. The method eliminates the influence of melanin pigmentation in the skin and creates on image that is devoid of melanin pigmentation and based on polarized photons scattered from within the superficial skin layer where much pathology arises. Hence, the doctor views an image which optimizes one's ability to directly discern the cellular structure of the superficial skin without interference from absorption due to melanin pigmentation. For example, dark pigmented nevi become clarified and subtle features in the epidermal/subepidermal space become visible. The images are compelling, but proper interpretation and future optimization of the camera system require a basic understanding of how polarized light scatters from the ultrastructure of tissues. The proposal has two aims. Aim 1 would address the underlying basis for contrast and depth of interrogation of the polarized video camera images. Aim 2 would investigate how the wavelength and angular-dependence of polarized light scattering can specify a unique fingerprint that characterizes the size and number density of light-scattering structures in the tissue ultrastructure. No human or in vivo animal studies are planned. Phantom tissues composed of polystyrene microspheres and animal tissue samples obtained from the abattoir will be studied. Computer simulations will complement experiments.